The present invention relates to a new and distinct cultivar of chrysanthemum plant, botanically known as Chrysanthemum×morifolium Ramat., commercially known as a garden mum, and hereinafter referred to by the cultivar denomination ‘Zanmubriwhi’. ‘Zanmubriwhi’ is a product of a breeding and selection program for outdoor pot mums (garden mums) which had the objective of creating new cultivars with a white double type inflorescence, a natural season flowering date around September 12, blooming for a period of 5 weeks. ‘Zanmubriwhi’ is a seedling resulting from a cross of the female parent 9375 (unpatented) with the male parent 57947 (unpatented). Plants of the new cultivar ‘Zanmubriwhi’ differ from plants of the female parent in the follow characteristics. (1) Ray-floret color and (2) Natural season blooming date. (1) Ray-florets are yellow in the female parent plant, and white in the new plant. (2) Plants of the female parent flower one week earlier than those of the new plant. Plants of the new cultivar ‘Zanmubriwhi’ differ from plants of the male parent in the following characteristics. (1) Plant size and (2) Natural season blooming date. (1) Plants of the male parent are smaller than those of the new plant. (2) Plants of the male parent flower one week earlier than those of the new plant.
The new and distinct cultivar was discovered and selected as a flowering plant by Henricus Cornelius Maria Jacobs on a cultivated field in Rijsenhout, The Netherlands in week 37 2012. The first act of asexual production of ‘Zanmubriwhi’ was accomplished when vegetative cuttings from the initial selection were propagated further in a controlled environment in Rijsenhout, the Netherlands. In summer, about 6-8 days are needed to initiate roots in cuttings of the new cultivar, after another 5 days rooted plants are formed. The new cultivar has been found to retain its distinctive characteristics through successive propagations.